1. Field of the Invention
The present invention generally relates to a quiet, compact and efficient burner for use with forced air heaters. More specifically, the invention relates to a porous ceramic gas burner constructed from ceramic blocks associated with each other to form a hollow chamber to receive naturally aspirated gas and air mixture from a venturi with the ceramic blocks including a plurality of small holes enabling passage of the gas and air mixture to the outer periphery of the burner for ignition and combustion with the structural characteristics of the small holes preventing flashback of flame even though the velocity of the air and gas mixture is less than the flame propagation rate thereby reducing the noise level of the burner by reducing the velocity of the air gas mixture passing through the burner. The burner is associated with a forced air heater including a fan and a duct associated therewith to direct forced secondary air over the periphery of the burner with the periphery of the burner including a surface generally parallel to the flow path of the secondary air with the holes in the burner being perpendicular to the flow path of the secondary air.
2. Information Disclosure Statement
Forced air heaters of various types are well-known and efforts have been made to provide such burners in a size that renders them portable. However, one of the problems which exists when reducing the size of a burner to render it feasible for use in a portable heater is the noise level produced by increased velocity of the air and gas mixture, increased flame speed and turbulence which is necessary in order to obtain desired heating capacity and efficiency. Usually, such burners introduce primary air in a manner that it mixes with the gaseous fuel before the mixture is burned which increases burning efficiency. This type of structure is relatively quiet as long as secondary combustion supporting air is naturally aspirated. However, the naturally aspirated secondary air burner is relatively large and not well suited for use in a portable forced air heater.
As a later development, portable forced air heaters have been provided with similar primary air burners which include forced secondary air which achieves good combustion performance with smaller size. However, along with the smaller size provided by the forced secondary air arrangement, the noise level of such burners increased substantially. An example of this type of forced air heater is found in U.S. Pat. No. 3,494,599 issued Feb. 10, 1970. While this type of heater is relatively efficient and provides sufficient heating capacity, the noise level is relatively high and is not compatible with adjacent personnel due to the noise level. The prior art in the field of portable forced air heaters does not disclose a burner structure that is sufficiently small or compact, efficient and provided with sufficient capacity for use with a portable forced air heater while maintaining noise at a sufficiently low level to enable its use with adjacent personnel.